1. Field of the Invention
This invention relates to finding the direction from which a radio signal was transmitted by gathering data about the signal and evaluating the signal's characteristics such as the angle of arrival azimuth/elevation, frequency, modulation, and signature wherein the receiver station is capable of determining the time of travel or bearing of the received signals with respect to the station by utilizing plural receivers as shown in claim 342/444.
2. Prior Art
The prior art shows two broad categories of systems: short base line receiving arrays where an electronic commutator samples signals sequentially or dual channel receivers which sample two antennas out of a set of antennas at a time and cross correlate to measure phase/time difference of arrival. The phase of the signals indicates the angle of arrival of the radio frequency signal.
These systems typically increase the number of successive scans to improve the accuracy of the determined bearing and are usually limited to determining azimuth and elevation angles of arrival. Other systems use directional antennas that are either manually rotated or use an electronic commutator.